Counterbalancing structure for disappearing stairway



y 1967 c. E. WEBB, SR 3,331,466

COUNTBRBALANCING STRUCTURE FOR DISAPPEARING STAIRWAY Filed Sept. 27, 1965 FIG.'2

e2 so 64 5a l8 INVENTOR. CLEITU S E. WEBB SR.

ATTORNEYS United States Patent Ofiice 3,331,455 Patented July 18, 1967 3,331,466 CGUNTERBALANCING STRUCTURE FOR DISAPPEARING STAIRWAY Cleitus E. Webb, Sr., Memphis, Tenn, assignor to Wel- Bilt Products Company, Memphis, Tenn., a co-partnership Filed Sept. 27, 1965, Ser. No. 490,368 4 Claims. (Cl. 18298) The invention relates to disappearing stairway structure and refers more specifically to improved counterbalancing structure for disappearing stairways or the like.

In the past counterbalancing structures for disappearing stairways and the like have generally included an actuating lever and resilient means operable to tend to pivot the actuating lever to move a stairway connected thereto in an up direction. Such structure has in the past often included resilient means which engages the ivot mounting for the actuating lever and which may be wrapped around the pivot mounting with the actuating lever in a position such that the stairway is open. Such construction is undesirable in that premature failure often occurs because of the added wear of the pivot mounting for the actuating lever and/or the resilient means due to their continued rubbing against each other in use. Additionally, the rubbing together of the parts of the counterbalancing structure produces objectionable noise in operation.

Further, the prior counterbalancing structures have usually depended only on the weight of the stairway with which they are associated for maintaining the stairway in an open position. Thus, in the past a slight jar or any sort of upward movement of the stairway has often caused the stairway to close, sometimes at undesirable or inconvenient times.

It is, therefore, an object of the present invention to provide improved counterbalancing structure for disappearing stairways or the like.

Another object is to provide counterbalancing structure for disappearing stairways or the like including an actuating lever, pivot mounting means therefor and resilient biasing structure connected to the actuating lever wherein the biasing structure is in spaced relation to the pivot mounting means in all positions of the actuating lever.

Another object is to provide counterbalancing structure for a disappearing stairway or the like wherein the stairway is biased to remain in a fully open position by the counterbalancing structure.

Another object is to provide counterbalancing structure including frame structure, an actuating lever having an arcuate end, means pivotally mounting the actuating lever adjacent the arcuate end to the frame structure, resilient means including a spring and a link connected together at one end, the other end of the link being pivotally connected to the arcuate end of the actuating lever and the other end of the spring being connected in a fixed position to the frame structure with the link and pivot mounting means being in spaced relation to each other.

Another object is to provide counterbalancing structure as set forth above wherein the link is formed at the pivot mounting means so that the point of connection of the link to the arcuate end of the actuating lever and the point of connection of the spring to the frame structure define a line extending below the pivot mounting means with the stairway in an open position.

Another object is to provide counterbalancing structure as set forth above including means for adju'stably securing the spring to the link at different points on the link.

Another object is to provide counterbalancing structure as set forth above and further including a positive stop abutment for the actuating lever defining the open position of the stairway.

Another object is to provide counterbalancing structure for disappearing stairways or the like which is simple in construction, economical to manufacture and eflicient in use.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawing, illustrating a preferred embodiment of the invention, wherein:

FIGURE 1 is a perspective view of counterbalancing structure constructed in accordance with the invention installed in conjunction with a disappearing stairway.

FIGURE 2 is an enlarged partial elevation view of counterbalancing structure constructed in accordance with the invention taken substantially in the direction of arrow 2 in FIGURE 1.

FIGURE 3 is a partial cross section view of the counterbalancing structure illustrated in FIGURE 1 taken on the line 3-3 in FIGURE 2.

With particular reference to the figures of the drawing, one embodiment of the present invention will now be disclosed in detail.

As shown best in FIGURE 1 the counterbalancing structure 10 is installed in ceiling construction 12 in conjunction with the disappearing stairway structure 14. In operation the counterbalancing structure 10 biases the stairway 14 to remain in either a fully open or closed position and aids in the moving of the disappearing stair way structure 14 into the closed position. Due to the particular construction of the counterbalancing structure 10 the operation thereof is particularly quiet and trouble free.

More specifically, the ceiling construction 12 may include upper floor boards 16 which may be supported on the usual framing joists or the like for such structure (not shown). The supporting frame 18 is then secured in an opening 20 in the floor structure 16 to additional frame members 22 which may be supplied around the opening 20 in the manner known in the disappearing stairway art.

The stairway structure 14 which is disclosed in more detail in United States Patent No. 3,051,261 includes the upper stair 24 pivotally secured to the supporting frame 18 by pivot mounting means 26 and the lower stair 28. The upper stair has the hand-rails 39 secured thereto. The lower stair 28 is secured to the upper stair 24 through the links 32 and 34 pivotally mounted at the ends to the upper and lower stair and biased by springs 36, as considered in detail in the above referenced patent. A closure 38 for the opening 20 is secured to the bottom of the upper stair 24 and functions to close the opening 2t} with the stairway structure 14 in a closed position.

The counterbalancing structure 10 includes the actuating lever 40 which has one arcuate end 42. The actuating lever 40 is pivotally connected at end 44 to the connecting link 46 which is in turn pivotally connected to the upper stair 24. The arcuate end 42 of the actuating lever 40 is pivotally connected by pivot pin 50 to the resilient structure 52. The pivot structure 54 is provided to pivotally mount the actuating lever 40 to the supporting frame 18.

Pivot structure 54, as best shown in FIGURE 3, includes a mounting plate 56 which maybe connected to the frame 18 by convenient means, such as screws 58. The mounting plate 56 is provided with an opening 69 therethr-ough and the actuating lever 40 is provided with an opening 62 therethrough aligned with the opening 6! in the mounting plate 56. The mounting plate 56 and actuating lever 40 are spaced apart by spacing cylinder 64 and the pivot pin 66 extends through the opening 69, spacing r 3 cylinder 64 and opening 62 to pivotally mount the actuating lever 40.

Resilient structure 52, as best shown in FIGURE 2, includes the bent or offset link 68 and the spring 70. Spring 70 is connected at end 72 to the frame 18 and is connected at the end 74 to the link 68 in an adjusted position determined by the partially stamped out and offset portions 76 of the link 68.

The link 68 is pivotally connected at end 78 to the actuating lever 40 by the pivot, pin 50. Link 68 is offset at the pivot structure 54 to extend downwardly and away from the spring 7 i with the actuating lever 49 in a position wherein the stairway 14 is open. With the link 63 formed as shown best in FIGURE 2, the line 80 between the mounting of the end 72 of the spring 70 and the pivot pin 50 is below the pivot structure 54 with the stairway in an open position.

The stairway 14 is thus biased to remain in an open position, as shown in FIGURE 1, until the stairway is closed sufiiciently so that the line 80 is above the pivot structure 54. Undesirable closing of the stairway is thus prevented. The force biasing the stairway o en may of course be determined by the distance between the line 80 and the pivot structure 54 with the stairway 14 in an open position.

In addition, it will be noted that with the counterbalancing structure, as illustrated in FIGURE 2, with the link 68 formed as shown, the link 68 is always in spaced relation to the pivot structure 54. Thus, there will be no excess wear between the link 68 or spring 70 and pivot mechanism 54 due to rubbing of the spring 70 or link 68 on the pivot mechanism 54 as the stairway structure is opened or closed. Also, with no engagement between the link or spring and pivot mechanism, the counterbalancing structure operates with a minimum of noise.

The abutment member 82 is generally L-shaped and is secured to the frame 18 by means of the screws 84, as best shown in FIGURE 2. The abutment member 82 provides a positive stop for the actuating lever 40 with the stair in a fully opened position to insure that the link 68 is always maintained in spaced relation to the pivot structure 54.

In overall operation of the disappearing stairway 14 and the counterbalancing structure 10 therefor, with the stairway 14 initially in a closed position the stairway structure 14 is pivoted in a clockwise direction about the pivot mounting 26 thereof toward the open position, as shown in FIGURE 1. During pivoting of the stairway structure 14 the actuating lever 40 is also pivoted in a clockwise direction about the pivot structure 54 whereby the counterbalancing spring 70 is tensioned so that it resists clockwise movement of the stairway structure until the stairway structure is very close to a fully open position.

At this time the line 80 defined by the pivot pin 50 and the mounting of the end 72 of the spring 70 passes down through the pivot structure 54. The spring 70 at this time tends to hold the stairway 14 in a fully open position until counterclockwise rotation of the stairway is effected sufficient to move the line 80 back through the pivot struc ture 54 in its upward movement. With the actuating lever 40 in a position wherein the stairway structure 14 is fully opened the lever 40 engages the abutment member 82. The link 68 is thus always maintained in spaced relation from the pivot structure 54, as best shown in FIGURE 3.

When it is desired tomove the stairway to a closed position the bottom stair 28 is pivoted into position on the upper stair 24 and the entire stairway structure is pivoted counterclockwise about the pivot means 26. The actuating lever 40 is thus also pivoted counterclockwise about the pivot structure 54 aided by the tension in the spring 70 7 'after the line 80 moves about the pivot structure 54. In

this movement the link 46 pivots about the pivot pin 48 to lie alongside of the end 44 of the actuatin-g lever 40. With the stairway 14 in a fully closed position the closure 38 covers the opening 12.

While one embodiment of the present invention has been considered in detail, it will be understood that other embodiments and modifications thereof are contemplated. It is the invention to include all modifications and embodiments as are defined by the appended claims within the scope of the invention.

What I claim as my invention is:

1. Disappearing stairway structure comprising a horizontally extending rectangular frame having parallel end members and parallel side members which frame is adapted to be secured in an opening in a ceiling or the like, stair structure pivotally mounted on the opposite sides thereof at one end to the side members of the frame adjacent one end thereof and counterbalance means operable between the frame and stair structure for selectively retaining the stair structure in a closed position within the frame and securing the stair structure in an open position pivoted out of the frame about the one end of the stair structure comprising an actuating arm including one end portion formed in an arc of substantially one hundred eighty derees, a pivot mounting for the actuating arm connected between the actuating arm adjacent the arcuate end portion thereof and one side member of the frame including means for maintaining the actuating arm in spaced relation to the one side member, a connecting link pivotally connected at one end to the stair structure centrally thereof and pivotally connected at the other end to the actuating lever at the other end of the actuating lever and resilientmeans connected at one end to the one end member of the frame adjacent the one end of the one side member and connected at the other end to the end of the arcuate portion of the actuating lever extending over the pivot mounting for the actuating lever in spaced relation thereto and between and in spaced relation to the actuating lever and the one side member of the frame, the connection of the resilient means to the arcuate portion of the actuating arm defining a line extending below the pivot mounting of the actuating arm in conjunction with the connec-' tion of the resilient means to the one end member of the frame with the stair structure in an open position pivoted out of the frame with the actuating arm extending substantially vertically whereby the stair structure is biased in an open position after it has been moved into an open position in opposition to said resilient means.

2. Structure as set forth in claim 1 wherein the resilient means comprises a helical spring one end of which is connected to the said one end member of the frame and an offset link one end of which is connected to the other end of the spring and the other end of which is pivotally connected to the end of the arcuate portion of the actuating member below the pivot mounting for the actuating member with the actuating member in a substantially vertical position. 3. Structure as set forth in claim 2 and further includmg means integral with said offset link for connecting the other end of the spring to the one end thereof at varied locations therealong. i

4. Structure as set forth in claim 1 and further including an abutment secured to the one side member, of the frame engageable with the actuating arm in the vertical position to limit the movement of the actuating arm in a stair structure opening direction.

References Cited UNITED STATES PATENTS 1,182,563 5/1916 Hild et al. 182-89 2,164,648 7/ 1939 Ferris 49-206 2,327,026 8/ 1943 Deuring 49-206 2,815,159 12/1957 Harmon l82-78 2,852,176 9/1958 Harmon 182-78 3,051,261 8/1962 Webb 132-78 REINALDO P. MACHADO, Primary Examiner. 

1. DISAPPEARING STAIRWAY STRUCTURE COMPRISING A HORIZONTALLY EXTENDING RECTANGULAR FRAME HAVING PARALLEL END MEMBERS AND PARALLEL SIDE MEMBERS WHICH FRAME IS ADAPTED TO BE SECURED IN AN OPENING IN A CEILING OR THE LIKE, STAIR STRUCTURE PIVOTALLY MOUNTED ON THE OPPOSITE SIDES THEREOF AT ONE END TO THE SIDE MEMBERS OF THE FRAME ADJACENT ONE END THEREOF AND COUNTERBALANCE MEANS OPERABLE BETWEEN THE FRAME AND STAIR STRUCTURE FOR SELECTIVELY RETAINING THE STAIR STRUCTURE IN A CLOSED POSITION WITHIN THE FRAME AND SECURING THE STAIR STRUCTURE IN AN OPEN POSITION PIVOTED OUT OF THE FRAME ABOUT THE ONE END OF THE STAIR STRUCTURE COMPRISING AN ACTUATING ARM INCLUDING ONE END PORTION FORMED IN AN ARC OF SUBSTANTIALLY ONE HUNDRED EIGHTY DEGREES, A PIVOT MOUNTING FOR THE ACTUATING ARM CONNECTED BETWEEN THE ACTUATING ARM ADJACENT THE ARCUATE END PORTION THEREOF AND ONE SIDE MEMBER OF THE FRAME INCLUDING MEANS FOR MAINTAINING THE ACTUATING ARM IN SPACED RELATION TO THE ONE SIDE MEMBER, A CONNECTING LINK PIVOTALLY CONNECTED AT ONE END TO THE STAIR STRUCTURE CENTRALLY THEREOF AND PIVOTALLY CONNECTED AT THE OTHER END TO THE ACTUATING LEVER AT THE OTHER END OF THE ACTUATING LEVER AND RESILIENT MEANS CONNECTED AT ONE END TO THE ONE END MEMBER OF THE FRAME ADJACENT THE ONE END OF THE ONE SIDE MEMBER AND CONNECTED AT THE OTHER END TO THE END OF THE ARCUATE PORTION OF THE ACTUATING LEVER EXTENDING OVER THE PIVOT MOUNTING FOR THE ACTUATING LEVER IN SPACED RELATION THERETO AND BETWEEN AND IN SPACED RELATION TO THE ACTUATING LEVER AND THE ONE SIDE MEMBER OF THE FRAME, THE CONNECTION OF THE RESILIENT MEANS TO THE ARCUATE PORTION OF THE ACTUATING ARM DEFINING A LINE EXTENDING BELOW THE PIVOT MOUNTING OF THE ACTUATING ARM IN CONJUNCTION WITH THE CONNECTION OF THE RESILIENT MEANS TO THE ONE END MEMBER OF THE FRAME WITH STAIR STRUCTURE IN AN OPEN POSITION PIVOTED OUT OF THE FRAME WITH THE ACTUATING ARM EXTENDING SUBSTANTIALLY VERTICALLY WHEREBY THE STAIR STRUCTURE IS BIASED IN AN OPEN POSITION AFTER IT HAS BEEN MOVED INTO AN OPEN POSITION IN OPPOSITION TO SAID RESILIENT MEANS. 